Impact of oral mucositis treated by photobiomodulation protocol on the quality of life of pediatric oncology patients with acute lymphoblastic leukemia.

To assess factors associated with methotrexate-induced oral mucositis and its impact on the quality of life of pediatric patients with acute lymphoblastic leukemia, considering chemotherapy dose and mucositis severity within a clinical context where photobiomodulation is routinely used as part of the institutional care protocol. A cross-sectional study was conducted with 113 pediatric patients aged 5 to 18 years undergoing methotrexate-based chemotherapy between 2020 and 2024 in a university hospital in Northeastern Brazil. Data were collected using the Children's International Mucositis Evaluation Scale (ChIMES; self-report and proxy), the Child Oral Impacts on Daily Performances (C-OIDP), the WHO Oral Mucositis Grading Scale, photobiomodulation records, and chemotherapy regimen data. Descriptive statistics, Spearman correlation, and multiple linear regression analyses were performed (α = 0.05). Among the participants, 85% reported a high impact on quality of life. The mean age was 10.8 years (SD = 3.49), and most participants were boys. Higher mucositis severity, older age, higher methotrexate doses, and longer wound healing time were associated with worse quality of life. A strong positive correlation was observed between C-OIDP and ChIMES scores (p < 0.001). In the regression analysis, mucositis severity (β = 0.304; p = 0.021) and wound healing time (β = 0.492; p < 0.001) remained significantly associated with higher impact scores. Methotrexate-induced oral mucositis was associated with a substantial negative impact on quality of life in pediatric patients with acute lymphoblastic leukemia. Greater mucositis severity and longer wound healing time were the main factors associated with worse outcomes. Although photobiomodulation was systematically applied as a preventive and therapeutic intervention, no causal inference regarding its independent effect can be established.